Патент USA US2125291код для вставки
Aug. 2, 193,8. R. B. HAYDEN 2,125,291 PRECIOUS METAL RECOVÈRY DEVICE Original Filed Feb. 11, 1935 2 Sheets-Sheet 1 î@ ATTORNEY Aug; 2, 1938.l R. B. |-|AYDE|~14 2,125,291 PRECIOUS METAL RECOVERY DEVICE Original Filed Feb. ll, 1955 2 Sheets-Sheet 2 f ßgéerïâ?’dydf/î INVENTOR `r gil-ORN EY I , 2,125,291 Patented Aug. 2, 1938 4PM‘ENT OFFICE UNITED STATES 2,125,291 PRECIOUS METAL RECOVERY DEVICE Robert B. Hayden, Seattle, Wash. Application February 11, 1935, Serial No.' 6,025 Renewed November 1, 1937 (Cl. 209-184) _ 12 claims. This invention relates to means for and meth-y ’ Fig. 2 is a view of the same partly in plan and ods of extracting precious metals from ñnely partly in section substantially on broken line Of Flig, 1. l divided ores, black sands and other ñnely divided I Fig.y 3 is a detached elevationy of a tubular feed Value bearing material. A primary object of this invention is to provide valve embodied in the invention. an eñicient means for and method of extracting precious' metals from ores which have been ground to a iineness which releases the precious metals or from other finely divided materials in 10 Which the precious metals occur in a free state. Another primary object of the invention is to provide means for and a method of extracting precious metals from finely divided concentrated material by bringing said material into intimate 15 contact with molten lead. Another primary object of the invention is to provide means for extracting precious metals from finely divided concentrated material, which O means may take the place of smelting at a much lower cost and with a much more efficient re covery of values. Another primary object of this invention is to provide efiicient means for extracting precious metals from finely divided value bearing material, which means is relatively inexpensive to manu facture and operate; is smalland compact in construction and readily transported to locations diihcult of access, thereby saving expense in curred in the shipment of concentrated material 30 to smelters; is capable of saving a very high percentage of all of the precious metals in ores or concentrates; and is capable of being suc » `cessfully operated by persons of ordinary skill. It is well known that a substantial amount of 35 values are lost in smelting processes by being carried away with the smoke and by-products-of combustion. My invention overcomes this -difñ culty and saves a large percentage of the values 40 ordinarily lost in this manner in smelting and at the same time provides a less expensive process of extraction. A still further object of this invention is to prevent losses of lead and values due to oxida tion in the course of the extraction treatment and to provide a method and means applicable to sub stantially all ñnely divided concentrates and .ores including complex ores. Other and more specific objects will be appar50 ent from the following description taken in con nection with the accompanying drawings. In the drawings, Fig. 1 is a view in vertical mid section, with parts shown in elevation, of a pre cious metal extraction device constructed in accordance with this invention. . Fig. 4 is a detached plan view of a mixing im peller embodied in the invention. Fig. 5 is a side elevation of said mixing impeller. Fig. 6 is a detached perspective view of a vane used on the bottom of a rotatably mounted float. 10 Fig. ’7 is a View partly in section and partly in elevation of a mixing receptacle embodied in the invention. Fig. 8 is a fragmentary sectional View illustrat ing a modified form of the invention. Like reference numerals designate like parts throughout the several views. Referring to the drawings, IU designates a bowl shaped receptacle which is supported on a suit able upright housing like frame II. The recep 20 tacle Ill is centrally provided with a relatively ilat conical bottom portion I2 of slightly concave shape on the inside. The conical bottom I2 has a centrally positioned outlet opening I3 controlled by a rotary valve I4. The valve I4 may have a 25 long stem I5 so that it may be operated from the exterior‘of the housing like frame II. Extending around the flat conical bottom portion I2 and integral with the receptacle Il] are a plurality of annular upright shoulders I6 and I1. At their 30 upper edges the shoulders I6 and I'I merge with annular flat shelf like portions I8 and I9 respec tively. Extending upwardly from the outer edge of the ñat shelf like portion I9 is an upper annu lar wall section'20 which is inclined inwardly to a point near the top of the receptacle and then has a short outwardly inclined portion 2| which terminates in a flat top portion 22. An annular vertical ñange 23 extends upwardly from the flat top portion 22. , 40 A feed hopper 24 is positioned above the re ceptacle 1_0 and preferably supported from the frame II by base members 25. The base mem bers 25 may rest on and be secured to the top of the receptacle I0, the receptacle I0 being sup ported directly on the frame I I. An upper frame member 26 is supported on the feed hopper 24 and extends upwardly therefrom to a substantial distancev above the hopper 24. A vertical shaft 21, having a lower end 28 of smaller diameter, is journaled in bearings 29- in the upper frame Vmember 26 and extends downwardly through the feed ‘hopper and into the receptacle I0. The up per frame member 26 is shown partially broken away in Fig. l, but said upper> frame member is 55 2,125,291 preferably made long enough to afford a good bearing arrangement for the shaft 21 and to allow the upper end of said shaft to be positioned tube 46 is of substantially larger diameter than the lower end portion 28 of the impeller shaft and said shaft 28 is externally provided within at a substantial distance above the hopper so the feed tube 46, with a spiral thread or worm that the driving connection at the upper end of said shaft will be less subject to the heat applied to the hopper and to the receptacle Ill. A belt pulley 35 on the upper end of the shaft 21 may be connected with a belt 3| by which the shaft is 41 which feeds ground material downwardly the the shaft rotates. This provides positive feed means for delivering the value bearing material into the mixing impeller. e Positioned within the upper portion of the re A mixing impeller, designated generally by 32, ceptacle lû is a relatively large heavy float 45. This float 43 is provided with a plurality of lugs is secured to the lower end of the shaft 21-28. 49 Which project beyond the peripheral portion driven. y, j n `r ' " ' l This mixing impeller embodies a disc like bot- ' thereof and are adapted to rest on the top 22 tom member 33 having a central hub into- 4which 15 the lower end of the shaft 21-28 may be thread ed. A ring like top member 34 is spaced above the disc like bottom member 33 and rigidly con-v nected with said disc likey bottom member 33 by peripherally disposed upright 1Janes 35.` These varies 35 are flat and are positioned at anv angle ,vars/respects radial` planes ofthe impeller. The Vanes «35 preferably havev integral rivets 35 on the ends thereof whichv are riveted into the ring „34 _andrbottom member 33. The function of these yvanes is to direct and propel material outwardly toward the »periphery ofthe receptacle lIU. An other set of vanes 31, integral withîor rigidly se cured to the- ring like top member 34,> are pro portie-n of the receptacle l@ and support the float when the device is not in use. When the device is in operation the float 48 is supported on the molten lead. The float 48 has a conical central opening 55 through which the feed tube 45 ex tends.y This opening 551s only slightly larger thanthe exterior of the feed tube 45 at the top 20 and said opening diverges or expands toward the bottom, portion of the ñoat. . Spiral thread means 5l provided within the conical opening 55B'. This thread means 5l helps to prevent lighter material from being crowded up through the openingA 55 by the heavier molten lead wh-en the ' device isin use. ' The peripheralrwalls 52 of the float 4B are in "clined conically and eonvergently from` bottom to r3.0 tend inwardly from ‘the ring like'top member 34 'top to conform 'to the incline of the upper wall1 toward -the axis of said `mixing» impeller. -The section 25 Vof the receptacle l0. The walls 52 of van'es v31I arepltched like the blades vof a propel the float 48 are spaced from the walls 2li of the ler and are adapted to exert a downward force receptacle Iii to afford an annular passageway von lmaterial which enters the impeller from the for the discharge of material which has been sub lL35 top. Bands 33, as of Wire, extend circumferen jected to the action of the molten lead. The bot tially around the impeller in engagement with tom of the float 48 is also of conical shape, as .135 the upright varies 35 and form screen like means indicated at 53, said bottom 53 being inclined up for breaking up the material which is passin-g wardly from the center toward the periphery.` radially outward through the impeller. The disc A plurality of vanes 54 are secured to the bot 40 like bottom member of the impeller is positioned tom of the float 48. These vanes, see Figs. l, 2 a short distance above the bottom Al2 o-f the re -and 6 are not radial but are positioned substan 40 tially tangential to the bottom portion of the The shaft 21428 is of larger diameter down conicalropening E50-and extend toward the pe to a'location a’short distance above the bot e riphery of the float. These Varies 54 Apreferably tomof the‘feed hopper and the lower end por terminate just inwardly from the shoulder l1 of tion 23 of said shaft is of smallerr diameter to the receptacle l5 so that said vanes 54 may ex 45 afford a material feed passageway 39. A tubular tend downwardly into the receptacle l5 inside of feedcontrol valve 4U' is provided on the exterior the shoulder I1. These vanes 54 are preferably `of theshaft 21. The lower end ofthe feed con shaped, as more clearly shown in Fig. 6, to pro 50 trol valv'e 45, Fig. 3, has upwardly extending feed vide base portions 55 arranged to be bolted to notches 4l through which ñnely divided mate the bottom of the iloat and vertical-1in portions rial may pass lfrom the feed hopper 24linto the 58-y and horizontal portions 51. These vanes 54 feed passageway 39 when the feed control valve form channels on the bottom of the slowly ro 40 is elevated into a position, as shown in Fig. 1. tating float 48, through which molten lead may 55 The upper end of the feed control valve 40 has flow back toward the axis of the machine and a lever 42 connected therewith. The lever 42 is beldelivered into the mixing impeller 32 on top> y.angularly movable over an inclined notched seg of the'incoming material from which the values -ment 4_3 Aon the rim of the feed hopper and is are tobe extracted. adapted to `-raise and lower the feed control valve An inlet opening 5S through which molten lead maybe introduced isprovided in the peripheral -60 40 and to hold said valve 40 in any desired ad 60 _justed position. In Fig. 1, the valve 40 is shown portion of the receptacle l0. at the upper limit of „its movement thus afford A discharge spout 59 is provided at the top ing a maximum feed. By moving the lever 42 of the receptacle l5'. The discharge spout 59 is vided at the top of the mixing impeller and ex ceptacle Ill.v ' . ` ~ toward the lower end of the inclined notched 65 segment 43 the feed will be decreased and said feed will be entirely cut off- when the feed notches 4l yare entirely within the passageway 39 in the hub portion 45 of the feedhopper 24. _ - A feed tube 46 is secured within the opening 70 39 inthe feed hoppern hub 45 and extends down Wardlyfinto thev mixing. impeller 32 so as to de liver’ñnely ground valuerbearing material di rectly into .saidmixing impeller. The ends of the preferably substantially tangential to the top of the receptacle lil and has an opening through the vertical flange 25 on the top> of said recep 65 tacle l0. The inner end of the discharge spout 59 is preferably level with the flat top portion 22 ,of the receptacle l0 and said discharge spout 59 is inclined downwardly toward Vthe outer end. The float 48 floats on molten lead 55 within the 70 receptacle I0 with the lugs 49 raised just clear of the lshelf portions 22.Y yA rotary motion is im `vanes 31. preferably terminate in close proximity '.parted to the molten lead by the rotating im tov theexterior >of the feed .tube~45. kThe feed peller and this rotary motion is communicated 75 ¿2,125,291 .3 to thelioat> 48. The lugs 49 on the float 48 are rate of speed and the feed control valve is opened moved around the receptacle I0 a short distance to allow material to feed downwardly. For a mix ',above'the flat shelf portion 22 of said receptacle . ing impeller of three inches over all diameter I findl that a speed of about 1750 revolutions per l0V and serve as means to sweep discharging ma minute, providing a peripheral speed of about <.terial outwardly into said spout 59. 1400 feet per minute, gives satisfactory results .; Receptacle heating means 6l is provided within but it will be understood that the angular and pe -the base frame VIl in operative relation with re spectV to the receptacle I8. This heating means ripheral speed of this impeller may be Varied de 6l is of sufficient capacity to maintain the lead „pending on various factors, as the size and shape 68 within the receptacle I0 in a molten condition of the impeller, shape of receptacle and char n10 it ybeing a characteristic of finely divided gold acter of material being treated. The rapid ro that it will liquefy at substantially 950 degrees tation of the impeller produces an outward and a -Fahrenheit when it is brought into contact with rotary motion of the molten lead in the receptacle lû and causes the molten lead to rise higher at molten lead. Another heating means 62 is also preferably provided for heating the material the circumference of the receptacle I0 and as 15 supply hopper 24 to keep the material in said sume a somewhat conical shape characteristic of liquids when rotated in cylindrical receptacles. hopper heated. In`> Fig. 8 I have shown a modiñed form of my When the molten lead is rotated in this manner it invention embodying a mixing impeller compris« will lift the float 48 so that the lugs 49 are clear ing a lower horizontal disc portion 63 secured to of the shelf like portion 22 on which they may U20 a rotating vertical shaft 64. An upper horizontal rest when the machine is not in operation. As disc portion 65 of larger diameter than the disc the ñoat is supported on the molten lead which portion 63 is secured to said disc portion B3, in is rotating in the receptacle the float will be spaced relation thereabove, by rivets 66 having caused to rotate at comparatively slow speed in the receptacle, due to the action of the rotating Vspacer sleeves. 61 thereon. A feed tube 68 ex molten lead on thevanes 54. This molten lead tends downwardly around the shaft 64 -and ter minates in an opening 69 which is provided in is also being driven toward the periphery of the receptacle l0 by the mixing impeller 32 and it the larger upper disc portion B5. The disc por tion 85 is provided on the bottom surface with a will flow upwardly along the outer receptacle walls plurality of downwardly extending’spaced apart and inwardly along the bottom of the float 48 30 between the vanes 54. This molten lead which lugs 'H0 which agitate and thoroughly mix ma fiows inwardly between the vanes 54 will pour into terial and molten lead which are directed out wardly by the impeller. ‘ These lugs 'lllvery thor-> the top of the impeller along with, and on top of, the incoming powdered valuebearing material oughly agitate and mix the material to be sepa rated because this material is lighter in weight thus bringing the molten lead into intimate con- il 35 than the molten lead and will continually tend to tact with the powdered material from which the values are to be extracted. The vanes 3l in the rise upwardly against the disc portion 65. In impeller will help to force this circulating molten clined vanes 'll are provided in the central por tion of the disc 65. These vanes 1l help to force lead down through the impeller and will keep the -40 the> material downwardly and outwardly. Other vlighter value bearing material forced down and f A40 vanes 'l2 are provided on the peripheral portion prevent it from rising through the impeller. The of the disc 65. The varies 'l2 are pitched so that `value bearing material is compelled to pass out they tend to force the material downwardly as it through the periphery of the mixing impeller and passes outwardly under said vanes. This secures is thoroughly mixed with the hot lead and gold and silver and all other precious metals having 45 a better mixing of the material with the molten aihnity for hot lead, will be absorbed and picked A receptacle 13 of modiñed shape is also shown up and held by the molten lead. The agitation in Fig. 8, this receptacle 13 has a concave bottom and whipping of the molten lead may cause a 'i4 of flattened cone shape and side walls 15 which portion of the lead and especially that portion are convergent inwardly from the bottom toward which has absorbed precious metals to flour or break up into small globules. This flouring may ` the top. i When this extraction device is to be operated be due to the action of oxygen in the material solid lead may be placed in the receptacle IIJ and being treated. This iloured lead, which hol-ds -melted or molten lead may be poured into the Values, together with the finely divided lighter receptacle l0 through the opening 58. Enough material or tailings will move outwardly along molten lead is provided to submerge the mixing the inclined bottom 53 of the float 48 and will impeller 32 and come into contact with the lower move upwardly between the internal wall of the portion of the float 48. The receptacle I0 is receptacle and the external wall of the ñoat 48 heated hot enough to keep this molten lead in and will be discharged through the spout 59. Some of the values will ordinarily be retained in 1 i60 FGO molten condition during operation.' The feed control valve 40 may be closed While the feed the molten lead in the receptacle which does not hopper is ñlled or partially ñlled with ñnely di ñour off. lead. ` ' vided or pulverized ore which carries values. This ore will usually have been previously roasted to its condition it for the extraction treatment and may come directly from an ore roaster. It will also have a suitable flux mixed with it which has been determined in the usual manner by the character of the ore. The feed hopper 24 is maintained at a high enough temperature so that the material to' be treated will not reduce the moltenlead be low the temperature necessary to liquefy the pre cious metals as it mixes therewith. The mixing itsV `impeller is then driven in the direction indicated by'thearrows in Figs, 1 and 4 at a relatively high The molten lead covered by the float 48 will not ' be expose-d to the air and will be protected against oxidation. The portions of molten lead toward: the center and toward the periphery which are not covered by the float will be covered by the pow dered material or tailings and will be protected from oxidation by exposure to the air. 710 n In the floured lead and tailings thus discharged some of the values will be held by the floured lead. The iioured lead may then be separated from the tailings in any well known manner, as by passing the' Same over _a concentrating table or by sub 2,125,291 jecting vsaid floured lead and tailings to a selective ceptacle; a driven rotary mixing impellerV posi tioned in the molten lead in said receptacle; said The floured lead with the values in it may then _ impeller having anropen center; a float in said be treated to recover the values. . I find that one receptacle floating in the molten lead and posi oil flotation process. ` method of recovering the values from this floured lead witha minimum loss of lead is to place the same in a receptacle, heat to a molten state and agitate the molten mass. I ñnd that agitation for a period of ten minutes is ordinarily sufficient. 10 This will cause the values to rise to the top while the lead which does not carry values will be left in the bottom of the receptacle. During this process the surface of the molten mass is covered with powdered lime rock or with -15 any powdered material which will prevent oxida tion. By providing a valve inthe bottom of the receptacle it is possible to draw 01T first the molten lead which does not carry values and then the molten lead which carries the values. The molten lead carrying the concentrated values may be separatedly collected and later treated in such a manner as to recover the values. Well known treatments for `the recovery of the con centrated values may be used. These treatments :25 usually involve they destruction or yloss of what lead> remains in the concentrated matter.` The re-melting, agitation and final concentra tion of the lead containing the values may be done in the receptacle Iû, preferably with the '.30 float 68 removed, and the lead drawn 01T through the valve l4'or a separate receptacle similar to the receptacle l0 -may be provided for this re melting agitation and final concentration. It is tioned above said impeller; the bottom of said float being conically inclined upwardly from the center outwardly and said bottom float wall ex erting a substantial pressure on the molten lead whereby material moving outwardly between said float and saidA molten lead will be subjected to pressure rolling and rubbing said material into saidmolten lead; and material feed means ex tending down through said float and connected with the open center of Vsaid impeller. 2. In a. mineral extraction device, a cylindrical heated molten lead receptacle; molten lead with in said receptacle; a driven rotary mixing im peller having a central material intake opening and peripherally directed material discharge openings and positioned within the lower portion of said receptacle; upright tubular feed conduit means communicatively connected with the ma terial intake openings of said impeller; and a relatively heavy float positioned in said recep tacle and floating in the molten lead and forming a top- wall spaced above said rotary impeller, the 25 bottom of said float being> conically inclined up wardly from the center outwardly and said float bottom exerting a substantial pressure î,on the molten lead whereby value bearing material mov ing outwardly between said float bottom and 30 said molten lead will be subjected to rubbing and rolling pressure, the periphery of said ñoat being also possible to allow this lead containing the ' spaced from the walls of said receptacle afford .35 concentrated values to cool and solidify after it has been re-melted and agitated and the values caused to rise to the top. If this is done the >values which have been caused to rise to the top ing a material discharge outlet. 3. In a mineral extraction device, a heated cy will not settle but will remain stratified at the .40 top of the' cooled, solidified lead ingot and this 54.5 value bearing top portion may be cut off and treated for the recovery of the values. When the values are thus caused to concentrate at the top of the molten lead it is found that there will be very little of the values left in the lead at the said receptacle; a driven rotary mixing impeller positioned in the lower portion of said receptacle, said impeller having an open periphery and a 40 hollow central portion; vanes provided in said hollo-W central portion forcing material down wardly in response to rotation in one direction of said impeller, other vanes provided in said open peripheral portion forcing material outwardly in If any values are left in the leadl in the response to rotation in the same direction of said 45 bottom of the receptacle they will not be lost as this lead is returned to the receptacle l@ and impeller; means rotating said impeller at a high rate of speed throwing lthe molten lead out of said impeller;v and an upright tubular feed conduit connected with the hollow central portion. 4. In a mineral extraction device, a heated cy 50 lindrical molten lead receptacle; molten lead in said receptacle; a driven rotary mixing impeller -positioned within said receptacle and having a central material intake opening and peripherally bottom. used over and over again. f The values which stay ,50 in the molten lead in the receptacle Ill may be recovered from this lead .in a manner similar to that above described after the lead in the recep tacle holds a. substantial amount of` values which do not fiouroff. New lead may be added to the 55 receptacle from time to time to replace the lead which ñours off. It has heretofore been found difñcult to recover values from finely divided ore bearing concen trates by the use of molten lead on a scale large 60 enough for commercial use. My invention pro vides a machine which may be used commercial ly at a great saving as compared to the usual smelting processes. This machine is efñcient in its extraction of values, not expensive to 65 35 lindrical molten lead receptacle; molten lead in manufacture and easy to operate. The foregoing description and accompanying drawings clearly disclose what I now regard as a ’ preferred embodiment of my invention but it will be understood Vthat this disclosure is merely illus 70 trative and that such changes in the invention may be made as are fairly within the scope and spirit of the following claims. I claim: - 1. In a mineral extraction device, a> heated 15 molten lead receptacle; moltenvlead in said re directed Vmaterial dischargeopenings; upright tu 55 bular feed conduit means communicatively con nected with the material intake opening of said ` impeller; a relatively heavy float positioned in said receptacle forming a top wall spaced above 60 the top (of said rotary impeller, the periphery of said float being spaced from the walls of said re ceptacle affording a discharge outlet for mate rial; and vanes on the bottom of said float ex tending from the central toward the peripheral 65 portion thereof. 5. In a mineral extraction device, a cylindrical receptacle; heating means operatively connected with said‘receptacle; molten lead in said recep tacle; an upright shaft extending down into said 70 receptacle; driving means connected with said shaft; a mixing impeller secured to the lower end portion of said shaft, said mixing impeller having a screen like peripheral portion and a hollow central portion; a feed hopper positioned above 75 5 2,125,291 said receptacle; a feed tube communicatively having a peripheral wall section which is in connecting said feed hopper and said mixing im peller, said shaft extending through said feed distance from the walls of said receptacle to provide a discharge outlet for material; and clined conically and divergently from the upper toward the lower portion of said receptacle and having a plurality of annular upright shoulders in the bottom thereof; receptacle heating means; a driven rotary mixing impeller disposed in the portion of said receptacle surrounded by said shoulders; said mixing impeller having a hollow center and having peripheral openings; ñoat 10 vanes on the bottom of said float extending from means forming a top wall above said mixing CII tube; a feed screw on said shaft within said feed tube; a circular float positioned in said recep-. tacle above said mixing impeller, the circumfer ' ential walls of said float being spaced a short impeller; the peripheral walls of said float being the central portion of the float outwardly. 6. In a mineral extraction device, a cylindrical receptacle; ~heating means operatively connected with said receptacle; molten lead in said recep 15 tacle; an upright shaft extending down into said receptacle; driving means connected with said shaft; a mixing impeller secured to the lower end portion of said shaft, said mixing impeller having a screen like peripheral portion and an inclined to conform to the incline of said conical receptacle walls and being spaced from said conical receptacle walls; molten lead in said re ceptacle submerging said impeller and contact ing said float means; and material feed means communicatively connected with said mixing impeller. 10. In a mineral extraction device, a recep screw on said shaft within said feed tube; a cir tacle, receptacle heating means; molten lead in 20 said receptacle; a driven rotary impeller posi tioned in the lower portion of said receptacle; said rotary impeller having material passageway cular ñoat rotatively mounted in said receptacle means extending from the upper axial portion to 20 open central portion; a feed tube communica tively connected with said mixing impeller, said shaft extending through said feed tube, a feed 25 above said mixing impeller and floated on the molten lead when the machine is in operation, the ,circumferential walls of said float being' spaced a short distance from the Walls of said receptacle to provide a discharge outlet for ma 30 terial; and vanes on the bottom of said float ex tending from the central portion of the float out wardly. 7. In a mineral extraction device, a receptacle having a plurality of annular upright shoulders 35 in the bottom thereof; receptacle heating means; a driven rotary mixing impeller disposed in the portion of said receptacle surrounded b-y said an nular shoulders, said mixing impeller having a the peripheral portion thereof; upright feed tube 25 means communicatively connected with said mix ing impeller; a float member rotatively sup» ported in said receptacle above said impeller, said float member having a cone shaped axial opening expanding from the upper end down wardly and fitting over said feed tube means; spiral thread means in said cone shaped opening; and vanes on the bottom side of said float sub stantially tangential to said conical opening. 11. In a mineral extraction device; a recep- , tacle, receptacle heating means; molten lead in said receptacle; a driven rotary impeller posi hollow center and having peripheral openings; tioned in the lower portion of said receptacle, said rotary impeller having material passageway 40 means rotating said impeller at a high rate of means extending from the upper axial portion speed throwing the molten lead outwardly from said impeller against said annular upright shoul ders; float means forming a top wall above said mixing impeller, the bottom of said float means being conically inclined upwardly from the center outwardly; molten lead in said receptacle sub merging said impeller and contacting and sup porting said float means; and material feed means communicatively connected with said mix tube means communicatively connected with said mixing impeller; a float member rotatively sup ported in said receptacle above said impeller and having a central opening through which‘said feed pipe extends, the peripheral walls of said ñoat member being spaced from the surrounding walls of said receptacle affording an outlet opening for material; lugs projecting from the periphery of said ñoat member; and an annular shelf on 50 50 ing impeller, said iioat means exerting a sub stantial pressure on the molten lead whereby ma terial between said float means and said molten lead vwill be spread out into a thin film and rubbed between said iioat means and the molten 55 lead. 8. In a mineral extraction device, a receptacle; having a peripheral wall section which is inclined conically and convergently from the lower toward the upper portion of said receptacle; receptacle 60 heating means; a driven rotary mixing impeller disposed in the lower portion of said receptacle, said mixing impeller having a hollow center and having peripheral openings; float means forming a top wall above said mixing impeller; the peri 65 pheral walls of said float being inclined to con form to the incline of said conical receptacle walls and being spaced from said control receptacle walls to provide an annular outlet opening; molten lead in said receptacle submerging said 70 mixing impeller and contacting said float means; and material feed means communicatively con nected with said mixing impeller. to the peripheral portion thereof; upright feed ' 9. In a mineral extraction device, a receptacle; said receptacle on which said lugs may rest, said float resting on the molten lead in the receptacle when the machine is in operation. 12. In a mineral extraction device, a receptacle, receptacle heating means; molten lead in said receptacle; a driven rotary impeller positioned in the lower portion of said receptacle, said rotary impeller having material passageway means ex tending from the upper axial portion to the peripheral portion thereof; upright feed tube 60 means communicatively connected with said mixing impeller, a float member rotatively sup ported in said receptacle above said impeller and having a central opening through which said feed pipe extends, the peripheral walls of said float member being spaced from the surrounding walls of said receptacle affording an outlet Vopening for material, said float member having a cone shaped bottom portion contacting the molten lead in said receptacle; and vanes on said cone shaped 70 float bottom extending from the central portion thereof outwardly. ‘ y ROBERT B. HAYDEN.